Fill limit control valve assembly having a liquid fuel trap

ABSTRACT

The subject invention includes a fill limit control valve assembly ( 10 ) having a valve portion ( 16 ) and a float portion ( 18 ). The valve portion ( 16 ) includes a vent opening ( 28 ) for venting vapors from the fuel tank ( 12 ) to a vapor canister. A float ( 30 ) is movably supported by the float portion ( 18 ) for movement between an open position spaced from the vent opening ( 28 ) and a closed position seating a seal ( 56 ) against a seat ( 64 ) about the vent opening ( 28 ). A liquid fuel trap or discriminator member is disposed above the vent opening ( 28 ) to limit liquid fuel flow through an outlet connector ( 22 ). The liquid fuel trap includes a baffle barrier ( 32 ) surrounding the vent opening ( 28 ) and a return cup ( 34 ) having a base ( 36 ) overlying the baffle barrier ( 32 ) and a depending rim ( 38 ) surrounding the baffle barrier ( 32 ) for forcing the flow of vapor from the vent opening ( 28 ) through a U-turn. A stem ( 54 ) extends from the top end of the float ( 30 ) downwardly to a distal end ( 58 ). A guide disk ( 60 ) extends across the float cavity and is in sliding engagement with the stem ( 54 ) for guiding and stabilizing movement of the float ( 30 ) in the float cavity between the positions. A spring ( 62 ) reacts between the guide disk ( 60 ) and the top of the stem ( 54 ) for biasing the stem ( 54 ) toward the closed position. During a rollover situation, the float ( 30 ) fills with fuel and does not float as it is forced against the seat ( 64 ) by the spring ( 62 ). A steel ball ( 72 ) engages and forces the distal end ( 58 ) of the stem ( 54 ) upward in response to the vertical axis of the valve, i.e., the axis of the stem ( 54 ), moving to a predetermined angle with vertical.

RELATED APPLICATIONS

This application is the U.S. national stage of PCT/CA00/00381, filedApr. 11, 2000, which claims the benefit of U.S. provisional applicationSerial No. 60/129,560, filed Apr. 16, 1999.

FIELD OF THE INVENTION

The present invention relates to a valve which controls the fuel level,the venting and traps fuel vapors from an automotive vehicle fuel tankto a fuel canister, or the like, and which prevents escape of liquidfuel from the fuel tank in the event of rollover of the vehicle.

BACKGROUND OF THE INVENTION

A fill limit control valve, which is normally disposed in a vehicle fueltank, frequently comprises a housing having a valve portion for sealingengagement about a hole in a fuel tank and a float portion extendinginto the fuel tank. The type of valve to which the subject inventionpertains responds to the level of liquid fuel in the fuel tank, stayingopen to vent vapor as long as the fuel level is below a predeterminedlevel. These are sometimes referred to as “fill control” or “shutoff”valves, since closing thereof creates a sudden pressure increase in thetank thereby preventing further refueling.

The valve portion defines a vent opening for venting vapors from thefuel tank and a vapor outlet for conveying fuel vapors to a vaporcanister. A float is movably supported by the float portion for seatingagainst and closing the vent opening in response to the float rising toa predetermined fuel level. Examples of such prior art assemblies areshown in U.S. Pat. Nos. 5,590,697 to Benj ey et al. and U.S. Pat. No.5,860,458 to Benjey et al.

Sometimes these valves are supplemented with a gravity-responsiverollover device supported at the bottom of the float portion forengaging and moving the float upwardly to seal the vent opening inresponse to a predetermined amount of deviation from vertical, e.g., arollover. An example of such a prior art assembly is shown in U.S. Pat.No. 5,809,976 to Cook et al.

Although all of these assemblies may perform satisfactorily, liquid fuelmay inadvertently pass through the valve and into the vapor canister.Influx of liquid into the vapor canister, can prematurely saturate thecanister and pollute the environment. Hence, there remains a need toreduce and virtually eliminate the amount of liquid fuel that passes outof the valve during normal operation.

SUMMARY OF THE INVENTION

The disadvantages of the prior art may be overcome by providing a filllimit control valve assembly disposed in a vehicle fuel tank. The filllimit control valve assembly has a housing having a valve portion forconnection to a fuel tank and a float portion for extending into thefuel tank. The valve portion defines a vent opening for venting vaporsfrom the fuel tank. A float is movably supported by the float portionfor movement between an open position spaced from the vent opening and aclosed position seating against and sealing the vent opening in responseto the float rising to a predetermined fuel level. A liquid fuel trap isdisposed above the vent opening to limit liquid fuel flow through thevapor outlet.

Accordingly, the subject invention provides a fill limit control valvethat mininmizes and virtually eliminates the undesirable flow of liquidfuel into a vapor canister. Hence, only fuel vapors pass through thevalve and into the canister.

According to another aspect of the invention, there is provided a filllimit control valve assembly having a float which traps vapor duringnormal fuel filling to enable the float to become buoyant andresponsively move to a closed position and which collects liquid fuelwhen in an inverted rollover condition to prevent buoyancy andresponsively move to the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is an environmental view showing the subject invention combinedwith an automotive vehicle fuel tank;

FIG. 2 is perspective view of a fill limit control valve in accordancewith the subject invention;

FIG. 3 is an enlarged perspective view in cross section of the subjectvalve in an open position;

FIG. 4 is an enlarged perspective view in cross section of the subjectvalve in a closed position; and

FIG. 5 is an enlarged perspective view in cross section of the subjectvalve in a closed and rollover position

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, a fill limit controlvalve assembly is generally shown at 10 disposed within a vehicle fueltank 12 in FIG. 1.

The valve assembly 10 includes a housing, generally indicated at 14,having a float portion, generally indicated at 18, adapted for extendinginto the fuel tank 12. The housing 14 includes a mounting cap 20defining a vapor outlet connector 22 for conveying vapors to a vaporcanister 24 via line 26. A recirculation pipe 21 is also provided on thecap 20 for recirculating vapors into a filler neck 23 via a second line25. In addition, a rollover valve 27 may be mounted to the fuel tank 12and connected to the vapor canister 24 as is known in the art.

The mounting cap 20 has a mounting face which abuts the fuel tank 12 tosecure the valve assembly 10 to the fuel tank 12 in any suitable manner.The vapor canister 24, which is typically a carbon canister, rollovervalve 27, and fuel tank 12 are of any suitable design as is known in theart. For illustrative purposes, the lines 25,26 are shown schematically.

Referring to FIG. 2, the float portion 18 is a cylindrical column andincludes a float 30 movably supported therein. The float portion 18defines a number of openings 82, 83 for providing fluid communicationbetween the fuel tank 12 and the float 30. As illustrated, the openings82 have a rectangular configuration and opening 83 has a triangularconfiguration. Preferably there are two rectangular openings 82 and twotriangular openings 83 diametrically opposed on the float portion 18.

Referring to FIGS. 3 and 4, the valve assembly 10 also includes a valveportion 16, adapted for connection to the fuel tank 12. The mounting cap20 encompasses at least a portion of the valve portion 16. The valveportion 16 defines a vent opening 28 for venting vapors from the fueltank 12 to the vapor canister 24 via outlet connector 22 and line 26.

The valve assembly 10 is characterized by a liquid fuel trap disposedabove the vent opening 28 to limit liquid fuel flow through the outletconnector 22. The fuel trap includes a baffle barrier 32 surrounding thevent opening 28. A return cup 34 having a base 36 overlies the bafflebarrier 32 with a depending rim 38 surrounding the baffle barrier 32 forforcing the flow of vapor from the vent opening 28 through a U-turn. Thereturn cup 34 includes legs 48 extending downwardly from the rim 38 tosupport the fuel trap in the valve portion 16. The return cup 34 alsoincludes a bullet 46 extending from the base 36 thereof and into thebaffle barrier 32 to define an annular passage for dividing the flow ofvapors from the vent opening 28. The bullet 46 extends above the base 36of the return cup 34 and an annular flange 50 extends radially of thebullet 46. The flange 50 has passages 52 therethrough for the passage ofvapors through the flange 50. The return cup 34, base 36, bullet 46,legs 48, and flange 50 preferably define an integral discriminatormember. The discriminator member preferably is formed of a homogeneousorganic polymeric material. As appreciated, the discriminator member mayinclude multiple separate parts and may be formed of any suitablematerial.

The valve portion 16 includes a bottom 40 supporting the baffle barrier32 and defining the vent opening 28. The bottom 40 of the integralcasing defines an annular valve seat 64 extending or projectingdownwardly. An outer wall 42 extends from the bottom 40 and is spacedfrom and surrounds the rim 38 for defining a collection reservoir forliquid fuel. The baffle barrier 32 includes drain holes 44 for drainingliquid from the reservoir back through the vent opening 28. The bafflebarrier 32, bottom 40 and outer wall 42 are all defined by an integralcasing, preferably formed of an organic polymeric material. The integralcasing may include multiple separate parts and may be formed of anysuitable material.

The legs 48 of the return cup 34 extending downwardly to the bottom 40for supporting the return cup 34, as well as the entire discriminatormember, on the bottom 40. The annular flange 50 engages the outer wall42 to further support the discriminator member to the wall 42 of thevalve portion 16.

The mounting cap 20 surrounds the outer wall 42 of the casing anddefines the vapor outlet connector 22 for conveying vapors from thepassages 52 in the annular flange 50 of the discriminator member. Theintegral casing and the cap 20 include a first tongue and grooveconnection 76 interconnecting the integral casing and the cap 20.

The float portion 18 defines a float cavity in which the float 30 isvertically movable between an open position spaced from the vent opening28 and a closed position seating against and sealing the vent opening28. The float cavity is defined by an extension of the integral casingwhich extends downwardly from the bottom 40. The float 30 includes abuoyant cylindrical section 31 having a closed top end connected to thetop of a stem or shaft 54. The cylindrical section 31 is hollow with anopen lower end and includes diametrically opposed openings 86 forallowing liquid to pass into a hollow interior of the cylindricalsection 31. Openings 86 are spaced from the closed upper end ofcylindrical section 31 so that a vapor chamber is defined having asufficient volume to enable the float 30 to float in response to thefilling liquid fuel.

A valve seal 56 is secured to the upper closed end of the cylindricalsection 31 for sealing engagement with the vent opening 28 to close thefloat 30 when in the closed position. As illustrated, the seal 56 isflexible and snapped into engagement with a button integral with the topend of the cylindrical section 31. Preferably, the seal 56 engages thevalve seat 64, which extends into the float cavity. The stem 54 extendsfrom the top end of the cylindrical section 31 of the float 30downwardly to a lower end 58.

A guide disk 60 extends about the lower end of the float cavity and hasan opening receiving the stem 54 for guiding and stabilizing movement ofthe float 30 in the float cavity. The guide disk 60 includes openings 84for allowing liquid to pass therethrough between the funnel-shapedelement 68 and the float cavity. A spring 62 acts between the guide disk60 and the top of the stem 54 for biasing the stem 54, as well as theentire float 30, toward the closed position.

Referring also to FIG. 5, a skirt 66 depends from the float portion 18of the integral casing. A gravity responsive device 67 is supported inthe skirt 66 of the float portion 18. The gravity responsive device 67is supported below the guide disk 60 for engaging the distal end 58 ofthe stem 54 and for moving the float 30 upwardly to seal with the seat64 and close the vent opening 28 in response to a predetermined amountof deviation from vertical.

The gravity responsive device 67 includes a funnel shaped element 68extending from a large diameter adjacent the guide disk 60 to a smalldiameter at the bottom thereof A ball-seat opening 70 is defined in thesmall diameter and a ball 72, preferably made of steel, is normallydisposed over the ball-seat opening 70. A support wheel 74 extendsradially from the small diameter to engage the skirt 66 to support thefunnel-shaped element 68 in the skirt 66. The guide disk 60 is alsosupported in the skirt 66. A second tongue and groove connection 78interconnects the disk 60 and the skirt 66. The wheel 74 and thefunnel-shaped element 68 are integral and consist of an organicpolymeric material and include a third tongue and groove connection 80interconnecting the wheel 74 and the skirt 66.

The invention provides a fill limit control valve assembly with anintegrated liquid/vapor discriminator member. During normal refilling ofthe fuel tank 12, the fuel level in the tank 12 rises and vapor isdisplaced. This causes a constant vapor flow to the canister 24. Inparticular, the vapors pass through the openings 82 and upwardly throughthe float cavity. The vapors then pass through the vent opening 28 andare then diverted by the bullet 46. The vapors pass over the bafflebarrier 32 between the barrier 32 and base 36. The vapors are forced tocomplete a U-turn by the depending rim 38. The vapors then continueupward through the passages 52 in the flange 50 and out through theconnector 22 and into the vapor canister 24. The vapors are purified bythe canister 24 and exhausted to the atmosphere.

The baffle barrier 32, in conjunction with the return cup 34, condensesfuel and fuel mist that travels with the vapor flow and retains anyliquid in the reservoir established between the wall 42 and the bafflebarrier 32. As appreciated, a small amount of fuel mist and/or liquidmay become trapped in the reservoir. This retained mist and/or liquiddrains back into the tank 12 through the drain holes or slits 44 in thebaffle barrier 32 once the vent opening 28 is reopened.

During normal filling of the fuel tank 12, at least a portion of theliquid fuel also passes through the openings 82 and into the floatcavity. The liquid fuel also passes through openings 84 in the guidedisk 60 such that liquid fuel is accumulating below and within the float30. In particular, liquid fuel is disposed between the stem 54 and thecylindrical section 31. The displaced vapor within the float 30 passesout of opening 86 within the cylindrical section 31. This processcontinues until the level of liquid fuel within the fuel tank 12 reachesthe level above the opening 86 in the cylindrical section 31. At thispoint, no additional vapors can pass through the opening 86 and thevapors disposed between the top of the cylindrical section 31 and theopening 86 are trapped within the upper end of the hollow interior ofthe cylindrical section 31, thereby increasing the buoyancy of the float30 allowing the float 30 to move responsively upwardly to the closedposition.

As the level of liquid in the fuel tank 12 continues to rise, the float30 will move from the open position, as shown in FIG. 3, to the closedposition, as shown in FIG. 4. The upward movement of the float 30 occursbecause of the buoyancy of the float 30, created by the trapped vapor,in relation to the rising liquid and the upward pushing force from thespring 62. Hence, when a predetermined level of fuel in the tank 12 isreached, the float 30 completely rises and, with the assistance of thespring 62, seals the seat 64 with the seal 56. The float 30 is thereforemovably supported by the float portion 18 for moving to the closedposition seating against and sealing the vent opening 28 in response tothe float 30 rising to a predetermined fuel level, i.e., full.

Upon closure of the vent opening 28, the fuel tank 12 no longer has anexhaust avenue for the vapor such that pressure builds up in the tank 12and corresponding filler neck 23. This pressure build-up triggers thefilling nozzle to shut off and stops the refilling of the fuel tank 12.

As the liquid fuel in the fuel tank 12 is used, the level of liquid fuelwill lower which subsequently lowers the float 30 within the floatcavity. As appreciated, the liquid fuel will flow out of the floatcavity through the openings 82. When the float 30 lowers, the ventopening 28 is reopened such that any trapped mist and liquid can flowback into the float cavity through the drain holes 44. The surfacetension of the fuel in the float 30 would cause the fuel to remain inthe cylindrical float 30 except that the stem 54 helps to purge the fuelby breaking this surface tension.

During a vehicle rollover, the steel ball 72 will disengage from theball-seat opening 70. Preferably, the steel ball 72 starts to roll outof the normal position when the vehicle is tilted more than 70°. As thesteel ball 72 moves upward along the funnel-shaped element, the ball 72engages the distal end 58 of the stem 54 to push the stem 54 into theclosed position sealing the fuel tank 12. As appreciated, the ball 72may be of any suitable design, material and weight so long as the stem54 is adequately pushed upward against the valve seat 64. During therollover, the cylindrical section 31 of float 30 will be in an invertedcondition and will therefore fill with liquid fuel such that the float30 is no longer buoyant. The float 30 is responsively forced to theclosed position, against the valve seat 64 by the spring 62 preventingfuel from passing through opening 28.

Many modifications and variations of the present invention are possiblein light of the above teachings. The invention may be practicedotherwise than as specifically described within the scope of theappended claims.

What is claimed is:
 1. A fill limit control valve assembly (10) adaptedfor disposition in a vehicle fuel tank (12), said valve assembly (10)comprising; a housing (14) having a valve portion (16) with an outletconnector (22) adapted for connection to a fuel tank (12) and a floatportion (18) for extending into the fuel tank (12), said valve portion(16) defining a vent opening (28) for venting vapors from the fuel tank(12), a float (30) movably supported by said float portion (18) formovement between an open position spaced from said vent opening (28) anda closed position seating against and sealing said vent opening (28),and a liquid fuel trap disposed above said vent opening (28) to limitliquid fuel flow therethrough to said outlet connector (22), said liquidfuel trap including a baffle barrier (32) surrounding said vent opening(28), and a return cup (34) having a base (36) overlying said bafflebarrier (32) with a dependent rim (38) surrounding said baffle barrier(32) for forcing the flow of said vapors from said vent opening (28)through a U-turn, and legs (48) extending downwardly from said rim (38)to support said liquid fuel trap in said valve portion (16), whereinsaid valve portion (16) includes a bottom (40) supporting said bafflebarrier (32) and defining said vent opening (28) and an outer wall (42)extending from said bottom (40) and spaced from and surrounding said rim(38) for defining a collection reservoir below said rim (38), saidbaffle barrier includes drain holes (44) for draining liquid from saidreservoir back through said vent opening (28), and said return cup (34)includes a bullet (46) extending from said base (36) thereof and intosaid baffle barrier (32) to define an annular passage for dividing saidvapor flow from said vent opening (28).
 2. An assembly as set forth inclaim 1 further including legs (48) extending downwardly from said rim(38) to said bottom (40) for supporting said return cup (34) on saidbottom (40).
 3. An assembly as set forth in claim 2 wherein said bullet(46) extends above said base (36) of said return cup (34) and includingan annular flange (50) extending radially of said bullet (46) to engagesaid outer wall (42), said flange (50) defining passages (52)therethrough for the passage of said vapors through said flange (50). 4.An assembly as set forth in claim 3 wherein said float portion (18)defines a float cavity in which said float (30) is vertically movablebetween said open and closed positions, said float (30) includes acylindrical section (31) which traps vapor during normal fuel filling toenable the float (30) to responsively move to the closed position andwhich collects liquid fuel when in an inverted rollover condition toresponsively move to the closed position.
 5. An assembly as set forth inclaim 4 wherein said float (30) further including a valve seal (56) at atop end for sealing engagement with said vent opening (28) to close samewhen in said closed position, a stem (54) extending from said top end ofsaid float (30) downwardly to a distal end (58).
 6. An assembly as setforth in claim 5 further including a guide disk (60) extending acrosssaid float cavity and in sliding engagement with said stem (54) forguiding and stabilizing said movement of said float (30) in said floatcavity between said positions.
 7. An assembly as set forth in claim 6wherein said valve seal (56) is supported on said top of said buoyantcylindrical section (31).
 8. An assembly as set forth in claim 7 furtherincluding a gravity responsive device (67) supported by said floatportion (18) below said guide disk (60) for engaging said distal end(58) of said stem (54) and for moving said float (30) upwardly to sealsaid vent opening (28) in response to a predetermined amount ofdeviation from vertical.
 9. An assembly as set forth in claim 8 furtherincluding a spring (62) reacting between said guide disk (60) and saidtop of said stem (54) for biasing said stem (54) toward said closedposition.
 10. An assembly as set forth in claim 9 wherein said bafflebarrier (32), said bottom (40) and said outer wall (42) define anintegral casing.
 11. An assembly as set forth in claim 10 wherein saidreturn cup (34), said base (36), said bullet (46), said legs (48), andsaid flange (50) define an integral discriminator member.
 12. Anassembly as set forth in claim 11 wherein said housing (14) includes amounting cap (20) surrounding said outer wall (42) of said casing anddefining said outlet connector (22) for conveying said vapors from saidannular flange (50) of said discriminator member.
 13. An assembly as setforth in claim 12 wherein said bottom (40) of said integral casingdefines an annular valve seat (64) extending downwardly into said floatcavity.
 14. An assembly as set forth in claim 13 wherein said integralcasing extends downwardly from said bottom (40) to further define saidfloat cavity with a skirt (66) depending therefrom.
 15. An assembly asset forth in claim 14 wherein said gravity responsive device (67) issupported in said skirt (66).
 16. An assembly as set forth in claim 15wherein said gravity responsive device (67) includes a funnel-shapedelement (68) extending from a large diameter adjacent said guide disk(60) to a small diameter, a ball-seat opening (70) in said smalldiameter, and a ball (72) normally disposed over said ball-seat opening(70).
 17. An assembly as set forth in claim 16 wherein said guide disk(60) is supported in said skirt (66).
 18. An assembly as set forth inclaim 17 including a support wheel (74) extending radially from saidsmall diameter to engage said skirt (66) to support said funnel-shapedelement (68) in said skirt (66).
 19. An assembly as set forth in claim18 wherein said float portion (18) includes openings (82) for allowingliquid to pass therethrough from the fuel tank (12) into said floatcavity, said guide disk (60) includes openings (84) for allowing liquidto pass therethrough from said funnel-shaped element (68) to said floatcavity, and said buoyant cylindrical section (31) being hollow with anopen distal end and including openings (86) for allowing liquid to passinto a hollow interior of said buoyant cylindrical section (31).
 20. Anassembly as set forth in claim 19 wherein said integral casing and saidcap (20) consist of an organic polymeric material and including a firsttongue and groove connection (76) interconnecting said integral casingand said cap (20), said disk (60) consisting of an organic polymericmaterial and including a second tongue and groove connection (78)interconnecting said disk (60) and said skirt (66), said wheel (74) andsaid funnel-shaped element (68) being integral and consisting of anorganic polymeric material and including a third tongue and grooveconnection (80) interconnecting said wheel (74) and said skirt (66).